This invention relates to an adjustment mechanism for a beater of a drum pedal enabling free adjustment of the beater amplitude and the pedal height.
In a conventional beater mechanism for a bass drum, shown for example in FIGS. 13 and 14, supports 92 are erected at both sides of the base 91 of a drum pedal device 90. A beater rotary shaft 94 is freely rotatably supported at the tops of the supports 92 through respective ball bearings 93.
There is a beater 110 approximately at the center of the rotary shaft 94, and next to the beater is an operating member 120, which is in the shape of a wheel. Both rotate integrally with the beater 110. The beater head 115 is fixed to the beater 110 by means of stopping screws 116.
The operating member 120 comprises a sprocket or a partial sprocket, with a chain 121 having an end that is fixed at the operating member 120 and is wound on its outer periphery. The other end of the chain 121 is linked to the tip of a foot pedal 95. As the foot pedal 95 is stepped on, as indicated by an arrow mark A in FIG. 13, the chain 121 is pulled down. This rotates the operating member 120 which in turn rotates the beater, thereby causing the beater head 115 to beat the drum head surface D.
A cam 100 is fixed at the end of the rotary shaft 94 by a stopper screw 101, as shown in FIG. 15. The cam 100 has the approximate shape of a fan, as shown in FIG. 13. At that portion which corresponds to the pivot of the fan, there is a shaft receiving hole 102 through which the rotary shaft 94 is installed. A plurality of roller installation holes 103 are provided at various positions over the cam.
A roller installation bolt 104 is screwed into one of the roller installation holes 103 selected dependent upon the initial pivot orientation of the cam 100. A hanging ring 106 is suspended from a roller 105 that is inserted into the roller installing bolt 104. The top of the spring 107 is engaged at the bottom tip of the hanging ring 106. The bottom of the spring 107 is engaged with a lower bracket 109 at the outside of the support 92. The strength of the spring 107 returns the beater 115 to its original position automatically. An adjustment bolt 108 adjusts the tension of the spring 107. A clamp 130 holds the drum pedal 90 to the drum hoop.
Amplitude adjustment of the conventional beater 115 involves changing the incline of the beater 110 through the beater rotary shaft 94, thereby changing the distance between the beater head 115 and the drum surface D, by changing the incline of the cam member 100 through selecting the positions of the plurality of roller installation holes 103 on the cam member 100. With such a conventional mechanism, however, it has been difficult to effect a fine adjustment based on the performer's wishes and the form of the performance because the amplitude position of the beater is determined, step-like, by the positions of the roller installation hole 103. Also, to adjust the beater amplitude position, the roller installation bolt 104 has to be removed and the spring 107 had to be changed each time, thereby consuming time for the adjustment.
In view of the foregoing circumstances, the inventor herein earlier proposed in Japanese Utility Model No. Hei 4-124295 a beater amplitude adjustment mechanism for the drum pedal using an arc shaped roller installation groove in the cam member with the beater rotary shaft at its center and with the roller being fixed in the installation groove so as to be freely adjustable in the drum pedal and where a cam is fixed at the end of a beater rotary shaft that is freely rotatably supported on a support and the spring is adjusted through a roller in the cam. This enables expressions of delicate sound quality because the amplitude of the beater can be adjusted without any steps merely by changing the rotary position of the beater rotary shaft as compared with the spring in the cam.
In either of the above described structures, where the beater and the operating member are fixed to the beater rotary shaft, however, a change in the rotary position of the beater rotary shaft in an attempt to adjust the amplitude of the beater would change the height position of the foot pedal through the simultaneous rotation of the operating member, thereby inconveniencing the performer.